If your wanting to save all your settings, game saves, documents, ect, you can use windows easy transfer (google it) to backup your user data.
once reinstalled if necessary, just re-run WET and it will all be back from the backup file.
It comes native in windows 7, but you can download it for older versions.
but as per your question, it all depends on how old the system is and how the drivers are setup. If its running under a native IDE driver, you can set up the amd board as native ide, it may work right away. Thats how I have my htpc hdd setup, transferred the system drive through 3 systems so far. If windows is loaded under any 3rd party drivers, AHCI, or Raid you would need to load drivers and hope it works.